Acknowledgment is given to
Leslie Muma, RN, MSN, NP for assistance in prepartion of this
learning module.

Description  The course is
designed as an elective to give the advanced practice nurse,
involved in the care of patients with cardiopulmonary problems, a
basic introduction to the principles of chest x-ray
interpretation. The course is in a self-programmed format whereby
the student reviews chest films with accompanying case histories
and answers. The chest films selected represent commonly
occurring cardiopulmonary problems in the primary care setting
and provide additional means by which nurses can correlate their
knowledge of pathophysiology and cardiopulmonary physical
assessment (theory and skills) with findings demonstrable on a
chest x-ray.

Grading  Choice of letter grade or
satisfactory/unsatisfactory. A satisfactory grade is obtained by
achieving 80% or greater on the post-test. The post-test may be
retaken as many times as necessary in order to achieve a passing
grade.

This schedule is given to be used as a
guideline to the practicum. The order of the films has been
selected to build and reinforce prior learning. The material to
be read may not follow exactly, but may be utilized as a
reference. Although Novelline is lengthy at times, it has the
best examples of films throughout the text. Felson and Basics of
Chest X-ray Interpretation: A Programmed Study (BCI) are
self-learning modules which you may use at your own pace.

 Place the films on the view box as
though you were facing the patient with his left on your right
side.

 An AP film, taken from the same distance
(6') enlarges the shadow of the heart which is far anterior in
the chest and makes the posterior ribs appear more horizontal.

 In a supine film, the diaphragm will be
higher and the lung volumes less than in a standing patient.

STANDARD LATERAL CHEST RADIOGRAPH 
left side of the chest against filmholder (cassette); beam
from right at a distance of six feet; lesion located behind the
left side of the heart or in the base of the lung are often
invisible on the PA view because the heart or diaphragm shadow
hides it; the left lateral will generally show such lesions; the
left lateral is thus the customary lateral view as it is the best
view to visualize lesions in the left thorax. Also, the heart
is less magnified when it is closer to the film.

 Good for viewing area behind heart
(retrosternal airspace  between the heart and sternum).

 Marked with a "R" or
"L" according to whether the right or the left side of
the patient was against the film  left lateral or right
lateral.

To visualize a lesion in the left thorax, it
is better to get a left lateral view.

To visualize a lesion in the right thorax,
it is better to get a right lateral view.

A fundamental rule of roentgenography  Try
to get the lesion as close to the film as possible.

PORTABLE CHEST X-RAYS  are AP
views (anterior Æ posterior); preferably upright but may be
supine, depending on patient's condition; taken with beam at
distance of 36 inches Æ blurring and magnification

In bilateral involvement of the lungs (as by
lymphoma involvement of the lower lungs), an oblique view avoids
the superimposition of a lateral view.

Sometimes used in studying the heart or hila of
the lungs; also in detailed study of the ribs.

The optimum degree of obliquity depends on the
site of the lesion being studied and the information desired
 it may have to be determined by fluoroscopy.

When we're too tired to think of whether we
need a right or a left oblique we just take both obliques.

Left Anterior Oblique
Left Anterolateral Chest Next to Cassette

Right Anterior Oblique
Right Anterolateral Chest Next to Cassette

Decubitus Views 
"decubitus" actually means "lying down;" made
with the patient lying on his side and the x-ray beam
horizontal (parallel) to the floor. Especially good to confirm
air-fluid levels in the lung.

Cross-Table Lateral (Horizontal) Views
 made with patient prone or supine and the beam horizontal
to the floor.

Lordotic Views  formerly made in
the upright AP position with the patient leaning backward at an
angle of ~ 30° from the vertical which was very awkward; now
made with the patient facing the film as for an upright PA view
but the tube is elevated and angled downward 45°.

Projects the lung apices of the lungs below the
clavicles and causes the ribs to project more horizontally.

Especially good for viewing the apices of the
lungs, lesions that are partially obscured by ribs, or the right
middle lobe or lingula of the left lung.

If the air on one side cannot be readily
expelled, the lung on the obstructed side remains expanded and
radiolucent on expiration.

Useful in detecting unilateral obstructive
emphysema (as from a unilateral obstruction of a bronchus).

A pneumothorax always appears larger on
expiration than on inspiration.

Since the thorax is smaller on expiration, the
unchanged volume of pleural air spreads out in the smaller
thoracic space.

Occasionally a small pneumothorax is only
visible on expiration.

Bucky Films  made with a moving
grid between the patient and the film which absorbs excess,
scattered radiation.

Scattered radiation produces a hazy, unsharp
image, or fog, and detracts from film clarity.

Used to delineate a thick pulmonary or pleural
lesion, bony structures, or to more clearly see structures in an
obese patient.

Bucky technique also used whenever the abdomen,
spine, mediastinum, pelvis, or heavy long bones are studied.

Tomography (Laminagraphy)

An apparatus moves the tube and film
synchronously in opposite directions; the adjustable fulcrum is
set to the plane of the lesion to be studied; blurs structures in
the planes above and below the level being studied.

If you can't think of the exact name for a
view, be descriptive or draw a picture (i.e., "Get me a
cross-table view with the patient lying on his right side facing
the tube.") or consult with the radiologist.

There are all sorts of ingenious projections
and fascinating special procedures in the armamentarium of the
radiologist.

 Structures which are perpendicular to
the plane of the film appear as they were much more dense as the
shadows represent the sum of the densities interposed
between the beam source and the film. Learn to think in terms of
those parts that are relatively parallel to the film and
those that are roughly perpendicular to it. Think about it
three-dimensionally.

 Thickness as well as composition
determine radiodensity. The shadow cast by a thick mass of soft
tissues will approach that of bone.

I. LABEL  Read the label on every
film to verify the patient's name, age, and sex.

II. ORIENTATION  Identify the
patient's right side, his position, and determine if he is
rotated.

Symmetrical spacing of the clavicles and other
structures on either side of the sternum; clavicles esp. will
show whether or not patient is straight or rotated. Symmetry of
the clavicles and ribs gives you assurance that no rotation is
present. Even slight rotation is undesirable in a chest film as
the heart and mediastinum are then radiography obliquely and
their shadows appear enlarged and distorted.

III. QUALITY  In a film of good
technical quality in a patient without gross cardiomegaly, you
should be able to see the outlines of the vertebral bodies within
the heart shadow; notice linearity of spine  is it
straight?

IV. INTERPRETATION: the following should
be identified:

A. Skeletal Structures  what you
see of the bones is incidental as the technique used for chest
films

has been designed for study of the lungs.
Always compare for symmetry.

1. Scapulae  PA and lateral; are
there two of each?

With hands on hips, palms out, and elbows
forward the scapulae are rotated to the sides to prevent their
superimposition upon the upper lung fields. Therefore only their
medial margins are seen.

2. Humeri and Shoulder Joints  PA
and lateral.

Little of the shoulder girdle and humerus will
be seen in films of broad-chested individuals.

Coracoid is seen through the spine of the
scapula because they superimpose.

Head of humerus and the acromium are also seen
additively.

Are fractures or abnormal calcifications (dense
white shadows) seen?

3. Clavicles  PA; symmetrical
spacing on either side of sternum only if there is no rotation of
the chest. Turned even a few degrees, the clavicles will exhibit
a remarkable degree of asymmetry.

4. Ribs  count on every film
to level of diaphragm.

Identify the first rib carefully by finding its
anterior junction with the manubrium and following this rib backward
to the spine. Then count down the posterior ribs.

Begin at the origin of the first rib at its
junction with the first thoracic vertebra and trace each rib as
far anteriorly as you can to the beginning of the radiolucent
(and hence invisible) costal cartilage.

Interspaces are useful in identifying the
location of a precise shadow and are named for the posterior
rib above the interspace unless the anterior rib is specified as
the marker.

The lung field under a missing breast will
appear a little darker than the other lung field.

C. Diaphragm

1. Difference in the Level of the
Hemidiaphragms

Right hemidiaphragm is normally a bit higher.

Impaired mobility of diaphragm  may be
from paralysis of either phrenic nerve, disease in abdomen such
as a subdiaphragmatic abscess, pleurisy, pulmonary infarction,
etc.

2. Normal Position

Distance from gastric bubble (if it is visible)
to diaphragm should be very small.

3. Shape of the Diaphragm.

4. Identification of Left and Right Diaphragms
 lateral film.

5. Costophrenic Angles

Should be sharp and clear.

No fluid density should be visible.

6. Cardiophrenic angle should be fairly clear.

7. Inferior vena cava adds its own little
shadow.

D. Heart and Great Vessels

Size of Heart  measure at widest
point; compare to size of thorax; should be no more than 1/2

the width of the thorax. Using any handy piece
of paper, determine the width of the heart. Then decide whether
this width exceeds the distance from the midpoint (spine) to the
inside of the rib cage (half the transthoracic diameter). Still
more simply, you can measure from the midline to the right heart
border and see whether that distance will fit into the piece of
lung field to the left side of the heart.

Assessment of the cardiovascular anatomy
includes assessment of heart and chamber size as well as the
position and size of the great vessels.

1 = right brachiocephalic
vessels

2 = ascending aorta and superimposed SVC

3 = right atrium (RA)

4 = inferior vena cava (IVC)

5 = left brachiocephalic vessels

6 = aortic knob/arch

7 = pulmonary trunk

8 = left atrial appendage (LA)

9 = left ventricle (LV)

Note: Normally concave slope between
arcs 6 and 9 is often called the "cardiac waistline."

Older smoker and vasculature not visible all
the way out = ? emphysema.

Younger person and not visible all the way out
= ? pneumothorax.

Pneumothorax = about the only thing that can
be diagnosed with absolute certainty with CXR.

7. Peripheral vasculature  follow it out
as far as you can see it.

 Hilum (pl. = hila).

 Position  higher or lower.

 Symmetry

Lung fields  symmetry re: amount of
density.

8. Silhouette Sign

2 densities that are alike with margins
adjacent to each other  borders will be masked.

If margin is obliterated, whatever is masked
and it has to be in the same plane.

Masking of RA  would be from R middle
lobe.

Masking of posterior diaphragm  would be
from R lower lobe.

Masking of LV  would be from L upper lobe
(anterior).

Masking of descending aorta  would be
from L lower lobe.

Masking of IVC and SVC  would be from R
lower and middle lobes.

If you can see heart  comes from
posterior.

9. Air Bronchogram Sign 
"butterfly" distribution of the abnormal densities or
an anatomic distribution of abnormal densities restricted to
lobar or sublobar portions of the lung.

Temporally rapid (reckoned in days) changes in
the appearance of the lung infiltrate.

Indicative of alveolar disease.

See airways out past bifurcation.

Air-filled airway superimposed on air-filled
densities.

Demonstration of the air-filled bronchus as a
radiolucent "tube" is dependent on its close
association with alveoli that are fluid-filled rather than
air-filled.

Two contrasting densities make it visible.

Airways OK, surround tissues not OK.

10. Kerley's Lines

Kerley's B Lines  short, thin horizontal
lines at the periphery of the lung near the costophrenic angles;
formed by thickening of the interlobular septa 2° to fibrosis
(e.g., pneumoconiosis), fluid accumulation, or distended
lymphatics-venules Kerley's A Lines  long, linear
densities, more centrally located in the upper portions of the
lungs near the hila; may be seen in interstitial lung disease and
CHF; represent swollen lymphatic channels.

F. Iatrogenics

1. ECG leads

2. Endotracheal tube  positioning

3. CVP and PA lines

INTERPRETATION OF CHEST FILMS

I. Skeletal Structures

A. Scapulae

B. Humeri

C. Clavicles  symmetrical spacing on
either side of sternum

D. Ribs

II. Soft Tissues  symmetry of
density.

A. Chest wall

B. Neck

C. Mediastinum

Trachea  is it midline, not shifted.

Identify bifurcation and position.

Should not be able to follow airways any
further out as they are very thin walled; if visible (air
bronchogram sign) - ?? pulmonary edema.

J. Relative position of L and R main branches
of pulmonary arteries  in relation to L & R main
bronchi

K. Esophagus  PA and lateral

L. Cardiac Size  normal is 1/2 or
less of the thoracic width on a PA film.

Simulation of cardiac enlargement  PA
films made in expiration (high diaphragm Æ heart tilted upward
bringing apex closer to the lateral chest wall + less flare of
ribs which alters the apparent cardiothoracic ratio); also any
abdominal distention (late pregnancy, ascites, intestinal
obstruction) produces similar results; diaphragm also likely to
be higher in supine views; portable chest films and other AP
views place heart farther away from the film.

Rotation of the patient produces appearance of
widening of the heart and mediastinal shadows.

Deformity of the thoracic cage  severe
scoliosis; depressed sternum (pectus excavatum) usually displaces
heart to the left + right heart border not visible.

Difference between heart volumes in systole and
diastole usually not enough to affect rough estimate of the
cardiothoracic ratio in adults.

Simulation of deceptively small heart
 overdistention of the lungs for any reason (dyspneic
patient with low diaphragm or emphysematous patient) compresses
the heart and mediastinal structures from both sides and narrows
their PA shadow.

Mediastinal disease, pulmonary disease, or any
density (consolidation, effusions, true mediastinal shift) may
render the dimensions of the heart unobtainable.

RADIOLOGIC SIGNS OF CARDIAC
DISEASE

Posteroanterior Projection

 The upper right border is formed by the
SVC and the lower cardiac border is formed by the RA. The left
border has three well-defined segments: The uppermost is formed
by the aortic arch, the main pulmonary artery lies immediately
below the aortic knob, and the lower left cardiac border is
formed by the LV and the apex. The LA appendage lies between the
pulmonary artery segment and the LV and is usually not seen as a
separate bulge.

Lateral Projection

 RV is the most anterior cardiac chamber
and is in direct contact with the lower sternum.

There should be a clear space (lung tissue)
between the sternum, the RV outflow tract, and the root of the
pulmonary artery, but pectus excavatum as well as RV enlargement
can impinge on this space.

The posterior cardiac border is made up of the
LA above and the LV below.

1 = right brachiocephalic
vessels

2 = ascending aorta and superimposed SVC

3 = right atrium (RA)

4 = inferior vena cava (IVC)

5 = left brachiocephalic vessels

6 = aortic arch

7 = pulmonary trunk

8 = left atrial appendage (LA)

9 = left ventricle (LV)

Technical Factors

 The heart appears larger on AP than PA
views.

 Film during expiration  simulates
pulmonary edema and the heart appears larger.

 One should check side markers for
dextrocardia.

 One should check the clavicles for
angulation.

 Overpenetrated films may miss heart
failure.

Extracardiac Structures

 Rib notching indicates coarctation of
the aorta. Rib notching = saucered erosions of the
undersurface of the ribs where dilated intercostal arteries have
developed as collateral pathways. Seldom present in children
younger than 10. Other conditions such as neurofibromatosis can
also cause rib notching.

Physiologic Analysis of the Pulmonary
Vasculature  appearance of the hilar and pulmonary
vessels is an excellent indicator of the physiologic state of the
heart.

Congestive Heart Failure

 _ size, shapelessness of heart, + evidence of pulmonary
venous engorgement  the vessels are seen to extend farther
than normal into the lung field.

 Bronchi become "framed" in the
interstitial fluid accumulating around them and, when seen
end-on, appear as white rings. This is often called
"peribronchial cuffing" and can be observed to decreaseas the patient
improves.

 Pleural effusion in cardiac failure may
be bilateral or unilateral and is more frequent on the right.

 Lungs appear hazy and less radiolucent
than normal because of retained water; lattice pattern.

 Kerley's B lines appear  short,
horizontal white linear densities very close to the peripheral
margin of the lung; have been proven to represent the thickened,
edematous interlobular septa; also seen in lymphangitic spread of
malignancies within the lung parenchyma and interstitial
pulmonary disease.

 Rapid accumulation of fluid spills over
into the alveoli and causes the development of alveolar
(air-space) pulmonary edema.

Pulmonary edema Æ the so-called
"bat-wing" appearance about both hila; superimposed
shadowsof innumerable fluid-filled alveoli may cause
disappearance of the vessels of the hilum; interstitial pulmonary
edema Æ
blurring of pulmonary vasculature; perihilar haze; may appear
rapidly after sudden LV failure or it may be superimposed on the
more gradual CXR findings of CHF.

Pulmonary edema can also occur in noncardiac
conditions such as fluid overload, renal failure, heroin
overdose, and inhalation injury or burns.

Plain films may show ventricular enlargement
but do not differentiate between hypertrophy and dilatation.

If heart is decompensating, it will tend to
shapelessness and extend to both the R and L in the PAview,
suggesting either failure or pericardial effusion. A review of
the patient's old films is probably the best way to assess
development of cardiac enlargement, in and out of failure.

 The echocardiogram is much more specific
for identifying structural abnormalities and chamber enlargement.
The echocardiogram also is very important for distinguishing
hypertrophy from dilation and recognizing pericardial effusions.

 CXR studies are most accurate in
detecting enlargement of the LA compared to the other 3 chambers.

 LA = most posterior of the cardiac
chambers and lies in the midline below the carina of the trachea
and the mainstem bronchus.

 LA has 2 distinct components  a
body and an appendage.

The body of the LA is centrally placed and does
not form a border on the frontal view.

The LA atrial appendage is to the left of the
body, immediately beneath the pulmonary artery segment, and above
the LV.

 The most common findings are a double
density of the right cardiac shadow, bulging the atrial appendage
along the middle of the left cardiac border on the frontal view,
and a posterior bulge of the upper cardiac border on the lateral
view.

 LA enlargement may eventually extend it
to the right so that its margin is visible along the right
heart border, above the profile of the RA and overlapping it
 the "double shadow" frequently referred to as a
classic sign of LA enlargement.

 Straightening of the L heart border may
be a normal finding; does not always signify increased LA size.

Filling in of the normally concave waistline
may be due to fullness that is either posterior (as in LA
dilatation) or anterior (as in any condition such as poststenotic
dilatation in pulmonic stenosis, or dilatation due to PDA).

 LA enlargement in mitral disease cardiac
enlargement  elevation of the L main bronchus just above
the L 8th rib, double shadow along the R heart border, ?
straightening of L heart border (? due to slight fullness of main
pulmonary artery).

Enlargement of the Left Ventricle

 LV forms the apex of the heart on the
frontal view.

 With dilation, the cardiac apex is
displaced downward toward the diaphragm and to the left; shadow
of aortic arch may be flattened.

 With hypertrophy, the apex becomes
rounded.

 LV enlargement often a/w aortic stenosis
and chronic HTN both of which may cause enlargement of the aorta.

 Lateral film  rounded posterior
projection of LV; border of heart is extended posteriorly and low
against the diaphragm.

Enlargement of the Right Side 
more difficult to recognize.

 RA forms the right lateral cardiac
border. The RV is normally an anterior midline chamber located
directly behind the sternum.

 RA enlargement fills in the space behind
the sternum.

 RV enlargement  enlarges in cor
pulmonale and in pulmonic stenosis; CXR (PA) may be deceptively
normal or show displacement of normal LV to the left.

Pulmonary artery often enlarged concomitantly.

May also see LV and LA enlargement if Lateral
film  filling in of the lower part of the anterior clear
space + flat posterior surface of the heart. Heart is not
extended posteriorly.

Chest X-Ray Findings with Myocardial
Dysfunction

 A large heart on CXR films supports the
dx. of systolic myocardial dysfunction.

 A lateral view is often helpful to check
for right-sided failure. If the space behind the sternum is
filled in, right-sided heart failure and RV dilation are
possible.

 Echocardiography is most useful for
identifying enlargement of a specific chamber and separating
dilation from hypertrophy.

 CXR can help rule in or out other causes
of dyspnea such as pulmonary fibrosis or COPD.

Chest X-Ray Findings with Myocardial
Ischemia

 Special x-ray imaging (fluoroscopy or
CT) can demonstrate coronary artery calcification, but this is an
uncertain marker. It has not had the test characteristics that
were originally anticipated because calcification of the arterial
walls is not necessarily a/w luminal occlusion, particularly in
older individuals.

Chest X-Ray Findings with Valvular
Dysfunction

 Signs of CHF and chamber enlargement can
be detected using chest x-ray studies.

 Valvular calcification can sometimes be
seen.

Chest X-Ray Findings with Poor Exercise
Capacity

 Signs of pulmonary disease can suggest a
noncardiac limitation to exercise and a large heart could suggest
cardiac disease.

 Signs of CHF can offer the possibility
of a cardiac cause for a change in exercise capacity.

Chest X-Ray Findings with Arrhythmias

 Films are of little use in the diagnosis
of arrhythmias. However, finding problems that are often a/w
arrhythmias, such as cardiac enlargement and lung disease, should
alter one to the possibility of arrhythmias.

 The straight back syndrome or pectus
excavatum was thought to be a/w with mitral valve prolapse and
arrhythmias.